EEPOET ON ICHTHYOLOGY. 415 



had erroneously represented the species, or that the drawing- had been wrongfully 

 interpreted by Rafinesque. It is also stated that there is no lateral line. This state- 

 ment is as certainly false as the other. The remainder of the description applies better 

 to the Pimelodus or Hoplodelus Umosus than to any other Siluroid of the Ohio. 



The generic diagnosis of Rafinesque describes the "Body scaleless, conical fat- 

 tened forwards and compressed behind. Head very broad and flat with barbs, eyes 

 above the head. Two dorsal fins, both with soft rays. Vent posterior.' 1 



The numbers of the rays of the fins are not given; but the description of the form 

 of the body and head, the position of the vent, the color, and we may even add the 

 popular name attributed to it, leave no room for doubt as to at least the generic iden- 

 tity of the Pylodirfis Umosus with the Hopladelus Umosus 



Another section, and the last one to be mentioned, into which Rafinesque divided 

 the Ictaluri, was placed as the third, and named Amciurus. His generic characters 

 are the following: 



"Tail entire. Eyes round. Eight abdominal rays. Vent posterior. Dorsal fin 

 anterior with a spine. Lower jaw not longer. Pectoral fins with one simple spine and 

 seven rays." 



This section corresponds to the restricted genus of which the common Pimelodus 

 catus and Pimelodus BeJcayi are the well-known representatives. Ra finest pie refers 

 to the section four species which appear to be truly congeneric. Dr. Kirtland, in his 

 "Descriptions of the Fishes of Lake Erie, the Ohio River, and their tributaries," refers 

 to only one of these — the Pimelodus cupreus. If we can rely upon the description of 

 Rafinesque, the Pimelodus lividus was not known to Dr. Kirtland. It may, however, 

 be the species described by that naturalist as Pimelodus catus. There is little doubt 

 that the same is the case with the Pimelodus melas. The Pimelodus xuntln-oecplialus, on 

 the other hand, appears to be only a variety of the Pimelodus cupreus of the same 

 author. 



In identifying the species of Rafinesque, we must, however, bear in mind that his 

 descriptions are generally so inaccurate or vague that of many of them we can never 

 be certain, and we can only have an approximate idea when the zoology of those places 

 which were so unfortunate as to receive his attention has been exhausted. That un- 

 happy man had, nevertheless, a keen appreciation of natural affinities; and had he been 

 less aberrant, he would have ranked far ahead of most of the naturalists of his day. 



As to the application of the name Pimelodus, it would appear necessary to reserve 

 it for one of those species referred to it by LacCpede which has not been placed in 

 other genera or groups, and which has been retained in the genus by its last monog- 

 rapher. . - 



the name of Heterobramhus sexteniaculatus. U lias a long second dorsal, which appears to be furnished with true rays. 

 On this character, Mr. Swainson has founded his gei - '' - E> ' " 



MlMiatxl l.\ thr ..,l,i nn-Ii.- !-'»/»»«■ (composed of true Atpral 



simultaneously, but Bleeker's has probably the priority. Swainson's name could not 

 applied, as it has been previously given to a valid genus of Chiroptera. 



